Electric machines, which are designed for high rated powers, may require cooling during operation, in order to particularly cool current-carrying components of the electric machine. In particular, a cooling of winding heads of one or a plurality of stator windings may be necessary, since these can greatly heat up during operation due to the currents flowing through them. Various possibilities for cooling such winding heads are known from the prior art.
A cooling arrangement for an electric machine is described in DE 10 2014 224 941 A1, in which a cooling oil can be introduced to the winding heads of a stator by way of oil lances arranged in the housing of the electric machine. In this case, the oil lances are connected via a distributor strip that is also arranged inside the housing. The cooling oil can be conveyed to the oil lances by way of the distributor strip.
DE 10 2012 019 749 A1 describes an electric machine for a motor vehicle drive train, in which a cooling oil can be introduced to the winding heads of the stator by way of a plurality of pipelines penetrating the housing. In addition to this, a heat exchanger is provided, which is arranged on a casing surface of a laminated core of the stator in order to enable an additional discharge of heat from the electric machine.
In EP 0 329 790 A1, a cooling system for an electric motor is described, in which a cooling oil is sprayed onto the winding heads from nozzles arranged on the front side. An improved cooling of the stator windings is achieved thereby when compared with a cooler disposed externally on the housing.